High-voltage circuit breakers

ABSTRACT

A disconnecting means for very high-voltage electrical installations, comprising a metallic enclosure for containing dielectric fluid, at least two electrical contact members each connected through insulating crossmembers to an exterior conducting element of the circuit to be disconnected, at least one earthed contact jaw, and a movable connecting element adapted to interconnect the two contact members of said circuit in one of its positions and of being earthed in another position, characterized in that said movable element carries a metallic guard part with which it is in permanent electrical connection, said guard part, when the moving element is earthed, automatically and jointly with the movable element assuming the role of a protective screen at earth potential, by being interposed between the contact members.

United States atem Bokshorn et al.

[54] HIGH-VOLTAGE CIRCUIT BREAKERS [72] Inventors: Yves Bokshorn, Villiers; Jean-Pierre ll.

Boudiak, Gagny, both of France [73] Assignee: COQ-Frauce, Pantim, France [221 Filed: Jan. 15, 1971 [21] Appl. No.: 106,811

[ Feb. 29, 1972 Primary ExaminerHerman J. Hohauser Attorney-Cushman, Darby & Cushman [57] ABSTRACT A disconnecting means for very high-voltage electrical installations, comprising a metallic enclosure for containing dielectric fluid, at least two electrical contact members each connected through insulating crossmembers to an exterior conducting element of the circuit to be disconnected, at least one earthed contact jaw, and a movable connecting element adapted to interconnect the two contact members of said circuit in one of its positions and of being earthed in another position, characterized in that said movable element carries a metallic guard part with which it is in permanent electrical connection, said guard part, when the moving element is earthed, automatically and jointly with the movable element assuming the role of a protective screen at earth potential, by being interposed between the contact members.

10 Claims, 7 Drawing Figures Patented Feb. 29, 1972 3,646,284

5 Sheets-Sheet l Patented Feb. 29, 1972 3,646,284

5 Sheets-Sheet 2 Patented Feb. 29, 1972 3,646,284

5 Sheets-Sheet 3 Patented Feb. 29, 1972 3,646,284

5 Sheets-Sheet 4 Patented Feb. 29, 1972 5 SheetsSheet 5 HIGH-VOLTAGE CIRCUIT BREAKERS The present invention relates to an improved disconnecting means for very high voltage electrical installations insulated in a gaseous or liquid dielectric, and more generally in a dielectric other than air at atmospheric pressure.

It is known that in such systems and in contrast to systems operating in air at atmospheric pressure, the idea of opening distance cannot be regarded as a valid criterion of safety. In fact, safety would depend upon the dielectrical rigidity of the insulating medium which could be momentarily adversely affected by an accidental unforeseen happening such as leakage of gas, pollution of the liquid, etc.

Furthermore, it is generally not possible to see the opening distance in the screened installations in which these methods of insulation are used.

To increase security, French specification UTE C 64 160,

Addition I, prescribes the use in the open position of constructive arrangements (form of the parts, guard ring, earthed metallic screen etc.), so that any start up or continuation can take place only when the installation is eartlhed, whatever the condition of the dielectrics and the waveform of the voltages applied over the opening distance."

Several solutions have been put forward for solving this problem. The following patentsmay be mentioned:

French Pat. No. 1,375,899 filed by Messrs. COQ-FRANCE on Sept. 10, 1963, but resulting from division out of an application of July 20, 1962, describes a linear-movement disconnecting means and a fluidtight metallic valve which is automatically interposed between the contacts of the disconnecting means as the latter opens.

The second solution is constituted by French Pat. No. l,348,593, filed on Nov. 30, 1962 by COMPAGNIE GENERALE DELECTRICITE. In this patent there is described a disconnection means comprising three insulating bushings of frustoconical form, two of which are fixed and the third is able to turn about a spindle. The latter, driven by a gear mechanism, converts its rotation into a translatory movement of a contact rod which effects disconnection. Upon completion of the opening stroke, by a second movement, a metallic screen which is not fluidtight is interposed between the disconnected contacts.

The third solution described in French Pat. No. 1,534,617 filed Aug. 24, 1967 by Messrs. N.V. COQ doesnot employ a screen, but the contact rod of the disconnecting means is automatically earthed in the open position by a separate element. This is possible because of a constructional feature which is based upon double separation and the use of an insulating wall which also acts as a mechanical support.

The three solutions are relatively complicated and difficult, and utilize at least two elements to effect disconnection and to interpose the protective device. These two elements must be joined and locked to each other.

The present invention proposes a quite different solution in which the two functions, namely, disconnection and positioning of the protective device are achieved by means of one and the same element of simple and inexpensive design, in a single movement.

The disconnecting means for very high voltage electrical installations in accordance with the invention comprising a metallic enclosure for containing the dielectric fluid, at least two electrical contact members each connected through insulating crossmemb ers to an exterior conducting element of the circuit to be disconnected, at least one contact jaw connected to earth, and a movable connecting element adapted to interconnect the two contact members of said circuit in one of its two positions and to be earthed in another position, is characterized in that said movable element carries a metallic guard part, with which it is in permanent electrical connection, said guard part, in the position in which the moving element is earthed, automatically and jointly with the moving element assumes the role of a protective screen at earth potential, by being interposed between the contact members.

In one embodiment of the invention, the movable connecting element is a rotating blade driven in the interior of the enclosure by a spindle made of electrically insulating material; the ends of said blade are applied to said contact members in a predetermined position and to at least one earthing jaw when said element is angularly displaced, at least the central portion of the latter being enclosed in a metallic mass forming a guard part.

In accordance with a further feature of the invention, the rotation of the blade actuates a signalling means which can be seen from the exterior.

In one method of reducing this feature to practice, the end of the rotating blade, at the moment when it establishes contact with the earth circuit, displaces a pusher which can be seen from the exterior of the enclosure, thus providing a visible signal indicating the earthed position.

The blade can close the electrical circuit of a low-current source in which is disposed a current-detecting means indicating the earthed position, which means may be luminous for example.

In a further method of reducing this feature to practice, the isolating spindle is hollow; a second coaxial spindle is contained therein; the two spindles are separately solidly connected to the rotating blades; the second spindle, which projects from the enclosure, carries an indicating means for showing the position of the blade.

In a further feature of the invention, the metallic enclosure surrounding said disconnecting means can be electrically associated with other enclosures also containing a dielectric. In one way of reducing this feature to practice, the enclosures adjacent to an enclosure containing said disconnecting means can contain a dielectric different from that contained in this latter enclosure.

In a further embodiment, at least one of the enclosures adjacent to an enclosure containing said disconnecting means contains the same dielectric as that contained in this latter enclosure, the enclosure or enclosures in question being interconnected by a pipe containing along its length a cutoff valve.

In accordance with a further feature of the invention, at least one metallic filter is placed in the pipe connecting two enclosures.

Other features and advantages of the invention will emerge from the following description which refers to the attached drawings, provided as nonlimiting examples, and which will clearly show how the present invention may be reduced to practice.

FIG. 1 is a sectional view of a disconnecting means in accordance with the invention, the section being along the axis of rotation of the blade.

FIG. 2 is a sectional view on line II of FIG. 1 and shows the disconnecting means in the position when the circuit is closed.

FIG. 3 is a view similar to that seen in FIG. 2, but showing the disconnecting means in the position when the circuit is opened.

FIG. 4 illustrates a modification of the arrangements shown in FIG. 3 as regards the means for effecting rotation of the blade.

FIGS. 5, 6 and 7 show portions of the electrical installation in which the means forming the subject matter of the present invention is used, the enclosure optionally communicating with other enclosures containing the same dielectric.

As can be seen in the various Figures, the disconnecting means of the invention is positioned in a fluidtight enclosure A which contains the dielectric fluid and is constituted by a metallic body 1, here having an almost spherical form and comprising two diametrally opposite openings la and lb closed by two transverse insulating parts 2a and 2b. Each of these insulating parts carries a contact 3a (or 3b) connected by a conductor 4 to an element such as 5 and 6 in the circuit to be disconnected.

The contact members 3a and 3b are diametrally opposed. An isolating spindle 7 is mounted to rotate in the opposite sides of the body 1 and is solidly connected to a blade 8 which, in one of its positions, is engaged by its ends 8a and 8b in the contact members 3a and 3b respectively so as to close the circuit between the elements 5 and 6.

This isolating spindle 7 can be actuated by any appropriate drive means 9, which may be mechanical, hydraulic and so on.

In a plane perpendicular to the plane of the contact members 3a and 3b, the body 1 carries at least one contact jaw 10 which is electrically connected to earth T and is adapted to grip one of the ends 8a or 8b in an angular position, in this embodiment, of 90 in relation to the position in which the contact members 3a and 3b are united.

According to the invention, the central portion of the blade 8 carries a metallic mass 11 in permanent electrical connection with the blade 8, and constituting a guard part between the contact members 3a and 3b, in such manner that in the position in which the circuit is open, the form of this part 11, combined with the form of the blade 8 which is at earth potential, prevents any direct jumping between the contact members 3a and 3b, and whatever the form in which an accidental internal arc develops, only an earth start can take place.

This guard part also acts as a deflector for the isolating spindle 7, thus ensuring suitable distribution of the potential.

It is well known that the official regulations call for a visual indication of the position of the connecting members, particularly for indicating the opening of the circuit and the earthing of the apparatus.

Because of the loads there may be a risk of the occurrence of a break in the connection between the spindle 7 and the blade 8, which break would allow an indicator fixed at the free end of the spindle 7 to show that the circuit was open when the blade 8 was still positioned between the contact members 3a and 3b, or at least had not yet reached the earthed position in which its end 8a should be engaged in the jaw 10.

To be certain about this position of the blade, the invention proposes that the end 8a should be caused to act on a pusher 12 which slides relatively to the body 1 and the free end 12a of which can be seen outside the body 1.

It is quite clear that this pusher would indicate that the circuit was open and the apparatus earthed only if the end 8a were effectively engaged in the jaw 10.

As can be seen from examining FIG. 4, it is possible to fit in one of the jaws 1011 a contact member 12a insulated from the earthed part and connected to a very low voltage electrical circuit supplied for example by a battery 13 and containing a current detector such as a lamp 14, which circuit closes when the rotating blade is in the earthed position and through this same blade and a contact member 12b, connected to the earthed part and positioned diametrally opposite the contact 12a, thus providing an electrical indicating arrangement.

A further solution is provided by the arrangement shown in FIG. 1 and wherein the spindle 7 is hollow, a second spindle 15 being arranged coaxially with the spindle 7 and carrying a pointer 16 at its free end 15a. The spindles 7 and 15 are separately connected to the blade 8 by connecting elements such as pins 17. Thus, even if the spindle 7 breaks, the pointer provides an exact indication since the spindle 15 correctly indicates the true position of the blade 8.

The enclosure A can of course be used in various combinations comprising similar enclosures, or enclosures of different types.

It will be seen in all the drawings that the transverse members 2a and 211 separate the enclosure A from the two adjacent enclosures B and C.

Because of the fluidtightness of each of the enclosures, a different fluid dielectric can be put into each of them. On the other hand however it may be important to connect one or more enclosures so that they communicate at least at a predetermined moment. This communication may be advantageously established by means of a pipe 18 of suitable cross section. This pipe may be controlled by a valve 19, e.g., a three-way valve.

In the position shown in FIG. 5, it is possible to supply and interconnect the insulating enclosures A and B; in the position shown in FIG. 6, said compartments can be insulated by means of air by supplying the compartment A; in the position shown in FIG. 7, said compartments can be insulated by means of air by supplying compartment B.

These possible arrangements enable one of the compartments to be acted upon in a simple and very safe manner, the other compartment remaining in operation.

This pipe 18 may also be fitted with a stop-valve 20, a nonreturn valve 21 and a draining cock 22. Finally, that portion of the pipe 18 giving access to the enclosures A and B can be fitted with a filter 23 made of porous metal, which in the event of accidental arcing in the enclosure A, enables the heated gases to expand without allowing the solid products of combustion to pass through.

We claim:

1. A disconnecting means for very high voltage electrical installations, comprising a metallic enclosure for containing dielectric fluid, at least two electrical contact members each connected through insulating crossmembers to an exterior conducting element of the circuit to be disconnected, at least one earthed contact jaw, and a movable connecting element adapted to interconnect the two contact members of said circuit in one of its positions and of being earthed in another position, characterized in that said movable element carries a metallic guard part with which it is in permanent electrical connection, said guard part, when the moving element is earthed, automatically and jointly with the movable element assuming the role of a protective screen at earth potential, by being interposed between the contact members.

2. A disconnecting means according to claim 1, charac' terized in that the movable connecting element is a rotating blade driven from the exterior of the enclosure by a spindle made of electrically insulating material, the ends of said blade being applied to said contact members in a predetermined position, and to at least one earthing jaw when said element is angularly displaced, at least the center portion of the latter being enclosed in a metallic mass constituting a guard part.

3. A disconnecting means according to claim 2, characterized in that rotation of the blade provides a signal visible from the exterior.

4. A disconnecting means according to claim 3, characterized in that the end of the rotating blade, at the moment when it provides contact with the earth circuit, displaces a pusher which can be seen from the outside of the enclosure, the earthed position thus being indicated.

5. A disconnecting means according to claim 4, characterized in that the blade closes the electric circuit of a low-current source in which is contained a current-detecting means, luminous for example, for indicating the earthed position.

6. A disconnecting means according to claim 2, characterized in that the isolating spindle is hollow, a second coaxial spindle is fitted in its interior, the two spindles are separately solidly connected to the rotating blade, and the second spindle, which projects from the enclosure, carries a pointer which indicates the position of the blade.

7. A disconnecting means according to claim 1, characterized in that the metal enclosure surrounding said disconnecting means can be electrically associated with other enclosures likewise surrounding a dielectric.

8. A disconnecting means according to claim 1, characterized in that the enclosures adjacent to an enclosure surrounding said disconnecting means may surround a dielectric different from that contained in this latter enclosure.

9. A disconnecting means according to claim 8, characterized in that at least one of the enclosures adjacent an enclosure surrounding said disconnecting means contains the same dielectric as that contained in said latter enclosure, the enclosure or enclosures in question being interconnected by a pipe comprising a cutoff valve along its length.

10. A disconnecting means according to claim 9, characterized in that at least one metallic filter is fitted in the pipe connecting two enclosures. 

1. A disconnecting means for very high voltage electrical installations, comprising a metallic enclosure for containing dielectric fluid, at least two electrical contact members each connected through insulating crossmembers to an exterior conducting element of the circuit to be disconnected, at least one earthed contact jaw, and a movable connecting element adapted to interconnect the two contact members of said circuit in one of its positions and of being earthed in another position, characterized in that said movable element carries a metallic guard part with which it is in permanent electrical connection, said guard part, when the moving element is earthed, automatically and jointly with the movable element assuming the role of a protective screen at earth potential, by being interposed between the contact members.
 2. A disconnecting means according to claim 1, characterized in that the movable connecting element is a rotating blade driven from the exterior of the enclosure by a spindle made of electrically insulating material, the ends of said blade being applied to said contact members in a predetermined position, and to at least one earthing jaw when said element is angularly displaced, at least the center portion of the latter being enclosed in a metallic mass constituting a guard part.
 3. A disconnecting means according to claim 2, characterized in that rotation of the blade provides a signaL visible from the exterior.
 4. A disconnecting means according to claim 3, characterized in that the end of the rotating blade, at the moment when it provides contact with the earth circuit, displaces a pusher which can be seen from the outside of the enclosure, the earthed position thus being indicated.
 5. A disconnecting means according to claim 4, characterized in that the blade closes the electric circuit of a low-current source in which is contained a current-detecting means, luminous for example, for indicating the earthed position.
 6. A disconnecting means according to claim 2, characterized in that the isolating spindle is hollow, a second coaxial spindle is fitted in its interior, the two spindles are separately solidly connected to the rotating blade, and the second spindle, which projects from the enclosure, carries a pointer which indicates the position of the blade.
 7. A disconnecting means according to claim 1, characterized in that the metal enclosure surrounding said disconnecting means can be electrically associated with other enclosures likewise surrounding a dielectric.
 8. A disconnecting means according to claim 1, characterized in that the enclosures adjacent to an enclosure surrounding said disconnecting means may surround a dielectric different from that contained in this latter enclosure.
 9. A disconnecting means according to claim 8, characterized in that at least one of the enclosures adjacent an enclosure surrounding said disconnecting means contains the same dielectric as that contained in said latter enclosure, the enclosure or enclosures in question being interconnected by a pipe comprising a cutoff valve along its length.
 10. A disconnecting means according to claim 9, characterized in that at least one metallic filter is fitted in the pipe connecting two enclosures. 